1. Field of the Invention
This invention relates to vehicular tires and particularly to channeled inserts adapted for use in pneumatic tires as a replacement for pressurized air.
2. State of the Art
One of the major problems associated with pneumatic tires currently in use is that if the tire is punctured or pierced by a pointed object, the pressurized air contained therein will escape causing the tire to deflate. When this occurs, the tire has absolutely no utility until the puncture is sealed. This problem is well known to anyone who drives or owns a vehicle and is a particular problem to those who own and/or operate bicycles having high pressure pneumatic tires as are commonly found on the popular ten speed bicycles. Prior to this invention, many types of inserts and various methods and techniques have been suggested as a solution for these problems. One of which is the use of tire inserts. Examples of patents which disclose the use of tire inserts include the following U.S. Pat. Nos.: 862,785; 918,846; 1,390,467; 1,819,632; and 1,506,411.
In each of the above patents, a means is disclosed whereby a rubber insert is placed within a tire casing to replace pressurized air. Each of the tubular inserts contain one or more cushioning chambers to simulate a pressurized pneumatic tire. One of the disadvantages of the inserts hereinbefore disclosed is that during use, the frictional movement of the inserts would generate heat and thereby cause deterioration of the tire casing's inner walls. Another problem is that there was no convenient means by which the prior art tire inserts could be constructed to insure a simulated pressure equivalent to the manufacturer's recommended pressure. In addition, many of the inserts disclosed in the prior art rely on the use of trapped ambient pressure to obtain a cushioning affect. In so doing, the tire can take on the characteristics of a partially flat or an improperly inflated tire when the trapped air is released by puncture.
In addition to the use of tire inserts, various other approaches have been suggested to render a tire puncture resistant. One technique is to add to a tire casing or inner tube a quick-curing substance which would enter a puncture and cause it to self-seal. Another approach was to produce a thicker inner tube while others have provided a double-walled inner tube. When the outer inner tube is punctured, the inner inner tube would retain sufficient air to permit the vehicle to be brought to a relatively safe stop. Still another approach was to insert a solid material, such as rubber or steel, within the tire casing of a pneumatic tire. If such a tire became punctured and lost its air, it would become only partially flat due to the support provided by the hard inner material.
A relatively recent innovation for preventing flat tires proposes a method for filling a pneumatic tire with a foamed rubber or plastic material and then curing the material within the tire. Upon completing the curing operation, the tire would be supported by the material introduced therein and would not require pressurized air. The above technique requires special and costly equipment to adapt to conventionally used tires and would not thereby be readily available to the average consumer.